Question. What constitutes a Duct Bank? There is no clear definition in the code book. We have a project where multiple runs of 4" GRC were installed in a ditch. Drawing indicates that if it's under AC pavement, it is to have concrete poured around it (no mention of duct bank). Only 60" feet of this run is under AC pavement so the concrete would only be around that portion. General contractor QC seems to think that becasue the note requires concrete, this constitutes a duct bank and thus has to have rebar, red concrete and specific size gravel in the concrete, as noted in a specification section entitled "underground electrical conduits". Opinions?